Mechanical tuning arrangement for dual helix winding antenna (compact antenna, 30-76 megacycles)



Doco 1968 R' M. MOOREHEAD 3,4 ,874

MBCHANICAL TUNING ARRANGEMENT FOR DUAL HELIX WINDING ANTENNA COMPACT ANTENNA, 50-76 MEGAGYCLES F11ed Dec. 10 1965 3 gr00ved druIns and threading the antenna (conduct0f) ont0 the drums. The conducting ribbons or tapes are stored on StationaTy reels 10cated at the end of the dmms The outer slotted cylindefs are held Stationary and Serve two functions:

(l) Enc10ses the tape, thus Inaintaining constant diarneter and constant length (2) (...uide the ends of the tapes lineafly While the gr00ved drums rotate.

One-half inch Wide tape vvas spaced 0Ilehalf inch apart on the drums with a Inaxin1u1T1 0f 18 turns on each drum' Theref0re, if the dmms r0tate at a maximum Speed of 200 r p.In ap 0xinTate1y 6 Seconds Will be Tequired to change the frequency from 30 to 76 mc The antenna mechanis[ns Were enclosed in a radon1e with maximum overall dimensions of 24 inches long by 6 inches high by 7 inches Wide These dilnensions include contouring for aerodynamic Strean1]ine.

The gr00ved drun1s and Slotted cylinders Were made of TeOn Which provides excenent electrical properties and a low coemcient of friction With the copper tape It is Seen that this invention comprises a Simple elec trically Small antenna capable 0f being tuned over a broad frequency 'ange and although this invention has been described With respect to a particular emb0diment there0f, it is not to be so limited, as changes and modincations Irlay be Tnade therein Which are Within the Spirit and Sc0pe 0f the invention as denned by the appended claims I claim:

1. A pair of variable inductors coupled t0gether comprising a pair 0f insulating drums rotatably suppofted parallel 0 each 0ther, a pair of Xed Slotted Cylinders extending over said drums, a first reel of eXible conducting tape mounted at the end of the firSt rotating dfum, a Second reel of exible tape Inounted at the end of the second rotati11g drum, a fifst clamp attached t0 the end of the first conducting (ape and rnounted in the S10t of the rst Slotted cylinder, a Second clamp attached t0 the end of the second tape and mounted in the slot of the Second Sl0tted cy1inder, and an electrica1 conduct01 connected betvveen the first and Second clanps.

2. In apparatus according to clailn 1 a driving means coupled t0 the first and Second drums to rotate theIn 3. In apparatus acc0rding to clain1 l, a pay-Out r()llel attached t0 the end of the rSt druIn adjacent the i'l[st reel and the irSt eXible tape passing over Said pay-0ut rolle1 onto the rst dfun1.

4. A variable inductor comprising a drum 0f insulating material, Hexible conducting tape, an insulated Slotted cylinder mounted about the drum, a clamp mounted bevveen the drum and cylinder within the slot, means for r0tating the drum felative to the cyinder, means for moving the clamp in the Slot aS the drum r0tates relative to the cylinder, and Said Hexible conducting tape attached t0 the clamp.

5, In apparatus according t0 claim 4 -'herein the means for moving the clan1p in the Slot comprises a spiral gr00ve formed in the drum 6. In apparatus according to claim 5 a reel for holding the eXible conducting tape adjacent the end of the drum, a lay-on n1echanism attached t0 the drum ada cent the reel and the Hexible tape passing froIn the reel over the lay-On mchaniSn1 t0 the drum.

7 In apparatus according to claim 6 Whefein Said lay-On nlechanisn1 C0Inprises a roller Supported from the dmm.

8 In apparatus according to clain1 `S Wherein the reel iS Supp0rted for lin]ited Totary In0tion adjacent the end of the drum.

UNITED STATES PATENTS z,993,182 7/196l Ems 3361 3,08,Zl 4/1963 shepherd 3437j0 x 3,zz6,72j lz/196S Ritchie et al 343750 

